iMX8QM-MEK HDMI Output 2400x900@60 Problem

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iMX8QM-MEK HDMI Output 2400x900@60 Problem

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nevozade
Contributor III

Hello,

I have built a yocto distro for fsl-imx-xwayland and iMX8QM-MEK machine with v5.4.70 kernel version as below.

yocto_imx8qm-mek.jpeg

I wish to output from 3 panels: 2 of them are LVDS outputs and 1 of them is HDMI output, all of them at the same time.

2 x panels have physical resolution 1920x720@60 and connected to iMX8QM-MEK eboard via LVDS lines with dual mode as represented figure below.

iMX8QM-MEK_LVDS_connection.png

1 x panel has physical resolution 2400x900@60 and connected to iMX8QM-MEK eboard via HDMI port.

* When I use the attached DTS file imx8qm-mek-hdmi.dts.txt, 2400x900@60 panel works fine which is connected to HDMI port. But there are no outputs on LVDS panels.

* When I use the attached DTS files imx8qm-mek-jdi-wuxga-lvds1-panel.dts.txt and imx8qm-mek-jdi-wuxga-lvds1-panel.dtsi, both 1920x720 LVDS panels work fine but there is no output on 2400x900@60 panel which is connected to HDMI port. If I unplug the HDMI connection from 2400x900@60 panel and plug a standard 1280x720@60 PC monitor via HDMI port, there is an output (works fine) on that PC monitor.

On the other hand, I have set the u-boot bootargs variable to adjust the HDMI output setting as below.

 

bootargs=root=/dev/mmcblk0p1 rootwait rw video=mxcdi0fb:RGB24,2400x900M@60,hdmi video=mxcdi1fb:RGB666,XGA,di0_primary ldb=di1 ip=none

 

How can I output from all of the panels (2 x LVDS 1920x720@60 and 1 x HDMI 2400x900@60) at the same time. What should be the rootcause of that problem ?

Note: DTS files are attached.

Regards,

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24 Replies

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tuncayyldrm
Contributor I

tempsnip.png

We cannot meet the criteria I show in the figure. What do I need to do to provide the resolutions in the options given here? 

Even though I took 2 LVDS and HDMI together, it was not possible to reach the resolutions I wanted and shown in the figure.

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OliverB
NXP Employee
NXP Employee

Can you provide the source for the slide "Seeris Display Output Capabilities"?

Can you also provide video mode definitions and/or EDIDs for the displays that you tried?

The current driver has a single display pipe width limit of 2560 pixels. This means that 2 2560 width displays are possible on a single display pipe. Which also means that up to 3 or 4 2560 width displays are possible. Or one larger display up to 5120 pixel width and two displays up to 2560 width.

Regards,

Oliver

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nevozade
Contributor III

Hi @OliverB ,

We had already shared the EDID of our panel you before as zipped file.

 

Thanks.

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hkaracali
Contributor II

Hello @OliverB  ,

We are trying to get at least 2 panels (one of them HDMI, one of them LVDS). Now 1 LVDS(1920x720) and 1 HDMI(1920x720) work fine. However when we changed HDMI with 2400x900 monitor, there is no image in the monitor. You can see reference slide as attached. Could you please give a way to find root cause of this issue?

Best regards.

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OliverB
NXP Employee
NXP Employee

hkaracali and  tuncayyldrm,

Are you working with nevozade? If not please, start another thread to avoid confusion. 

nevozade, 

Can you provide the full boot log as follows:

  1. Leave the HDMI monitor unplugged boot until the prompt. Both LVDS panels should be working. (If not you need to investigate.)
  2. login
  3. run "dmesg -c"
  4. Run "modetest"
  5. plug in the HDMI monitor.
  6. run "dmesg -c"
  7. run "modetest"
  8. Save the full console dump and send it to me.

Sorry to keep asking for logs, but this may be the only way I can help?

Regards,

Oliver

 

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tuncayyldrm
Contributor I
Spoiler
 

Hello @OliverB,

When we tried to get the log you requested from us, we encountered the error that the 'modetest command not found'. Several solutions we found on the internet did not help us run the modetest command. We saw the message that libraries such as libdrm-dev already newest version installed when we tried to install some libraries. Do you have an alternative for modetest or an idea to solve this problem instead ?

 

Regards.

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OliverB
NXP Employee
NXP Employee

You may be using the core-image-minimal. Can you start a new yocto build with imx-image-multimedia or imx-image-full?

Alternatively, you could use the prebuilt images to test this also from here:

 https://www.nxp.com/webapp/Download?colCode=L5.4.70_2.3.0_MX8QM&appType=licens

Then you could build the kernel sources from here:

https://source.codeaurora.org/external/imx/linux-imx 

branch: remotes/origin/imx_5.4.70_2.3.0

Remember to apply the patch attached here. I found the dts file was missing -  sorry. So use this patch!

And Finally set the boot environment: 

=> setenv fdt_file imx8qm-mek-jdi-wuxga-lvds0-lvds1-panel-hdmi.dtb
=> saveenv
Saving Environment to MMC... Writing to MMC(1)... OK
=> boot

 

Regards,

Oliver

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nevozade
Contributor III

Yes @OliverB , we are working together on this issue, you can accept their replies like I wrote.

No problem for us to ask logs or other files, we all aim to solve this problem. Sorry for responding late, we are in very far time zones. We are going to provide what you requested.

Thanks,

 

Nevzat

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hkaracali
Contributor II

Hello @OliverB,

Yes. We are working with nevozade. So we can go on from this issue. We will send logs tomorrow. Because we are not in the office right now because of time zone difference.

Best regards.

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OliverB
NXP Employee
NXP Employee

I was able to get HDMI working with LVDS0 and LVDS1. The HDMI display needs to be limited to 2560 pixels or less and less than 300MHz pixel clock. Otherwise LVDS0 will not have a display. In this patch I also had to disable hdmi audio due to a probe conflict. Let me know if this is working for you. 

 

Regards,

 

Oliver

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nevozade
Contributor III

Hello @OliverB ,

Firstly, thanks for your quick reply, this issue is so urgent and important to me.

I have applied your patch and 1 HDMI and 2 LVDS work now. However still I have a problem. Now just I can get 1920x1080 resolution from HDMI; but I need 2400x900 like FHD+. Without your patch if I use imx8qm-mek-hdmi.dtb, HDMI (2400x900) works; but not any LVDS. If I use imx8qm-mek-jdi-wuxga-lvds1-panel.dtb, just 2 LVDS work, no HDMI. When I apply your patch 2 LVDS OK; just HDMI (1920x1080) OK, not 2400x900. What is the reason of not working 2400x900 with LVDSs and how can I solve this problem? Or is this case possible?

Best regards.

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OliverB
NXP Employee
NXP Employee

Hi Nevozade,

I'm not sure why it is not working for your resolution. Can you you provide the EDID from you 2400x900 monitor? You can just provide the output of "modtest" from when your monitor is working in HDMI mode. I'll have to set this mode on my analyzer and see what is causing the problem. Both the display controller driver and HDMI Driver should allow this mode in a single display pipe. It's possible "1920"  is hardcoded somewhere in the drivers.

Regards,

 

Oliver

   

 

 

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nevozade
Contributor III

Hi @OliverB ,

Actually, we analyzed the EDID of our monitor before and we saw that 2400x900. According to your request, I am sending you the edid file for you to analyze and find the problem. I am asking for your support in this matter. (I attach the file as .zip because the .bin extension has failed to upload)

Best Regards,

 


Nevzat

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OliverB
NXP Employee
NXP Employee

I verified that HDMI 2400x900 and two LVDS 1920x1200 can work with your edid and 0001-arm64-boot-dts-freescale-Add-configuration-for-two-L.patch. I did not need any uboot changes or weston.ini changes. I also previously verified that 2560 width can work, this would be the upper limit of the width for a single display pipe.

Also the settings below are not for iMX8QM and should not be used:

video=mxcdi0fb:RGB24,2400x900M@60,hdmi video=mxcdi1fb:RGB666,XGA,di0_primary ldb=di1 

These are for iMX6DQ with IPUv3. 

To force a DRM mode the form should be 

video=HDMI-A-1:2400x900-32@60

 

My patch supports the dual-channel 1920x1200 NXP display panel, so some change would be needed to get change the panel and disable dual channel mode.

 

Regards,

 

Oliver

 

 

 

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nevozade
Contributor III

Hi @OliverB,

Although I think I'm doing it right, just in case could you zip and share the freescale folder (including dts and dtsis) in build/tmp/work-shared/imx8qmmek/kernel-source/arch/arm64/boot/dts/ path with me? I want to make sure I'm doing the same thing you did before I move forward.

Thanks.

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OliverB
NXP Employee
NXP Employee

Here are the device tree files. I hope they helps. 

Regards,

Oliver

 

 

 

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nevozade
Contributor III

Hello @OliverB 

Even I use your patch, HDMI 2400x900 and LVDS not working for me. If I disabled lvds-channel@0 HDMI works. If I make "okay" lvds-channel@0 LVDS works. It seems when HDMI starts to work LVDS disabled automatically. You can my final dts as attached. What is the reason of this issue?

Best regards.

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OliverB
NXP Employee
NXP Employee

Can you provide the full log from powerup to the linux prompt?

 

Regards,

 

Oliver

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nevozade
Contributor III

Hi @OliverB ,

  • The case that 2 LVDS panels work together, but HDMI (2400x900) does not work -> lvds.log and imx8qm-mek-jdi-wuxga-lvds1-panel-LVDS.dtsi
  • The case that HDMI (2400x900) works, but no display on LVDS panels -> hdmi.log and imx8qm-mek-jdi-wuxga-lvds1-panel-HDMI.dtsi

All specified files exist in the attached zip file.

Best Regards,

 

Nevzat.

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OliverB
NXP Employee
NXP Employee

Can you try this file? The LVDS nodes were disabled. 

All three display are working with this file included as follows:

--- a/arch/arm64/boot/dts/freescale/imx8qm-mek-jdi-wuxga-lvds1-panel.dts
+++ b/arch/arm64/boot/dts/freescale/imx8qm-mek-jdi-wuxga-lvds1-panel.dts
@@ -5,4 +5,4 @@
*/

#include "imx8qm-mek.dts"
-#include "imx8qm-mek-jdi-wuxga-lvds1-panel.dtsi"
+#include "imx8qm-mek-jdi-wuxga-lvds1-panel-HDMI-fixed.dtsi"

 

 

Regards,

 

Oliver

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